Data Protector Deduplication Guidelines - HP StorageWorks 12000 - Virtual Library System EVA Gateway Manual

Data Protector Deduplication Guidelines

In addition to the Data Protector general guidelines, the following guidelines apply to a VLS with
deduplication enabled:
• Patch all Windows clients: HP Data Protector on Windows clients requires a software fix to elim-
inate 56 KB file fragments that diminish deduplication performance on VLS and D2D products.
The fix depends on your version of Data Protector:
• DP 6.0: install the patch DPWIN_00426 (or later patches). Download the patch from the HP
website on the Data Protector version 6.0 "Download drivers and software" page.
• DP 6.1: included in the 6.11 service pack. If this is not yet available, request SSPNT610_012
(which you can automatically deploy to all Windows Disk Agent clients) through the Data
Protector support channel.
• Disable multiplexing in Oracle RMAN backups: In the VLS firmware version 3.3.0 (or higher) the
scripting requirements for Oracle data files have been relaxed, so it is no longer mandatory to
assign prefix naming conventions to Oracle data files to make sure the data is properly deduplic-
ated. The minimum requirement for RMAN to deduplicate efficiently is to disable multiplexing
(where you have multiple RMAN streams concurrently writing to the same drive). You can disable
multiplexing by setting concurrency to 1 in Data Protector and setting FILESPERSET=1 for each
database backup in the RMAN scripts (not needed for archive logs or control files). You can define
additional channels to increase the number of parallel backup processes running with FILESPER-
SET=1 to generate the same RMAN performance as before, so that each stream goes to a different
virtual tape drive.
The following RMAN settings will not deduplicate because they always generate totally unique
data every backup:
• Incremental backups
• RMAN compressed backups
• RMAN encryption
NOTE:
If you had previously configured the prefix naming conventions in your Oracle RMAN scripts, this
will continue to deduplicate efficiently with the firmware version 3.3.0 (or higher), but you should
ensure that multiplexing is disabled as well. If you wish to remove the prefix naming conventions,
you will need to rename the backup job name in Data Protector. (New backup jobs will not
deduplicate against the previous jobs with the different job name.)
• Allocate Unformatted Media First: If you have deduplication enabled, you should disable the
"Allocate unformatted media first" option in the media pool. You must also set the global variable
InitOnLoosePolicy=1 defined in the global file and the Data Protector services must be restarted
for the global variable to take effect. In HPUX the file is located in /etc/opt/omni/server/
options/global, and in Windows the file is located in C:\Program Files\OmniBack\
Config\Server\Options\global. These settings prevents Data Protector from using all
available blank cartridges for backups before it starts overwriting expired/scratch cartridges;
creating too many virtual cartridges results in the device disk capacity filling up.
• Interactive backups will not deduplicate: If you edit a Data Protector backup specification and
then manually run it from the GUI without saving it, the backup session will run with a backup
specification name of 'Interactive' and therefore will not deduplicate. This is because deduplication
correlates backup versions using the backup specification name.
• Full and incremental backups with different names: Some Data Protector configurations have dif-
ferent backup job names for full backups and for incremental backups (for example, to have dif-
HP StorageWorks VLS and D2D Solutions Guide 195